Termination of tenancy

The tenancy of any land held by a tenant shall not be terminated unless such tenant,- (a) has done any act which is destructive or permanently injurious to the land; or (b) has used such land for a purposes other than agriculture; or (c) has sub-let the land or assigned any interest therein except to the extent provided in section 20: Provided that nothing in clause (c) shall apply to sub-letting of any land held by a tenant who is a widow or a minor or who is subject to physical or mental disability.